Polyphosphate composition containing tarnish inhibitor



: 2,861,044 "POLYPHQSPHATE COMPOSITION CONTAINING H Y Y TARNISHINHIBITOR" Edgar E. Ruff, and Robert E. Dukeshire, Cambridge, Mass., assignors to'Lever Brothers'f Company, 'New Yor-k, N. Y.,acorporation ofMaine I I Y No Drawing. 'Application July 8, 1950 e Serial No. 172,776 t 16 Claims. (Cl. 252-137) I invention relates to polyphosphate compositions containing tarnish inhibitors, and, more' particularly, to detergent compositions containing polyphosphate build ers and tarnish inhibitors.

A wide variety of compositions containing polyphos copper alloys such as G erm'ansilve'r' '(anickel zi'ri'c cop peralloy) to' a variety of shades from yellow to bluish black if permitted to remainin contact therewithfor-sev- 3 eral minutes, especially if the solutions are at elevated temperatures. This is a serious problem in the detergent art; for 'German silver is frequently. used for. household I articles commonly washed in polyphosphate-containing 2 detergent compositions;

Since I detergent compositions containing phosphates, suchjas sodium orthophosphate, do not cause tarnishing, v v

(2) Z-mercaptobenzothiazole or its tautomeric form, the 7 3 .E.. %X.z un

Z therefore is a substituent which does not react with or inhibit the anti-tarnishing activity of this group, and

' preferably is selected from thegroup consisting of hydrogen, oxooxygen, alky1,. such as methyl, aryl,p,such as ,phenyl; or diphenyl,- .and.;saturate d and-unsaturated mono and polynuclear =alicyclicand het'erocyclierings, such as cyclohexyl or. benzene rings, condensedwith, ire

" sharing two carbon atoms with,:the above heterocyclic the difliculty could be avoided by using phosphate build- 51 as other than the polyphosphates. This, is undesirable,

however, because polyphosphates display a synergistic efiect with many detergents, and for this reason are highlyregarded by the art. 1 1

Accordingly, it is an object of the present invention to provide a tarnish inhibitor for polyphosphate compositions. I I

'[It is a furtherobject to incorporate with compositions containing polyphosphates amaterial" which will inhibit the tarnishing of metals, and particularly the tarnishing of German silver, by such compositions.'

It is a further object of the presentinvention to provide a detergent composition containing polyphosphate builders anda tarnishiinhibitor therefor, which compositio' n will-,not. tarnish metals such as German silver. 7 "@Thetarni'sh inhibitors in; accordance with thelinventi'on'are five-membered heterocyclic ring compounds 'c'ontaining in the ring a nitrogen atom and an atom of an element of group VI of the periodic table selected from the group consisting of oxygen and sulfur, spaced from the nitrogen atom in the ring by one carbonatom. The said ring carbon atom bears as a" substituent a mercapto radical.

Those skilled in the art will recognize these as thiazole, thiazoline, oxazole and oxazoline compounds.

having a mercapto group substituted at the Z-carbon position. These heterocyclic compounds may be represented by the general structural formula where X is selected from the group consisting of oxygen and sulfur and Z is a radical or radicals taken in sufiicient number to satisfy the free valences of the Nos. 4- and S-carbon atoms.

These carbons have two free-valences in oxazoles and thiazoles, and four free 'va'lences sring in a polycyclic systemnr, Rings condensedt. therewith may bear nonin'terfering .1 substituents,: such. .ashalogen,

amino, alkyl and aryl groups.

"*bond" between the 4- and S-carbon atoms in the oxazoles and thiazoles.

The following compounds are examples of those which have structures within the limits of the above general formula, and are suggested for use as tarnish inhibitors:

( 1) 2-jrnercapto-4-phenylthiazoline Cfi '(3) 6-amino-2-mercaptobenzothiazole (4) Z-mercaptothi PB? p w s, (5) 2-mercapto-4,5 dimethylthiazole. g-

(7) Z inercapt'ooXaZOIine (8) 2 mercaptothiaz'oline (10) Z-mercaptooxazole V (H) 4,4-'dimtiiyI-Z hrercaptodxazoline GIL-L; srr

( 12) Z-mercap tocyclohexylthiazoline" to 1% by Weight of the polyphosphate) of one of the tarnish inhibitors listed in the following table to i a standard commercial detergent, composed of the following ingredients in the proportions specified:

Percent Magnesium phenylpolypropylene sulfonate 34 Tetrasodium pyrophosphate and pentasodium tripolyphosphate p i Other builders, water and inert materiaL", 18

Aqueous solutions containing 5 g. composition in. one quart water of 60 p, p. rn..hardness were prepared and brought to 165 German. silver utensils were immersed in thesesolutions ,for thirtyminutes at 165 F. and. then taken out, rinsed lightly with warm water and dried. The effectiveness of the tarnish inhibitorin preventing tarnish was not'edjand rated on the same scale as in Example I'. The results wereas follows:'

am l Peroeut Axuountoi Inhibitor Tarnish Inhibitors" in. 10.50 o.25 0.125 boss 0.631

Phenylbiguauidosalt of 2-mercapto- (1) (1) (2) benzothiazole. O-tolyl 'biguanidolsalt biz-memento beuzothiazole. O-biphenyl biguanirie salt of z mercap tobenzothiazoia' Zinc salt. otQ-rnercaptohenzothrazole Benzyl"hexamethylenetetramine salt oi2-nrezcaptohenzothiazole;g. i 6-au1ino-2-mercaptobenzothiazole 2-mercapto-4,5-dirnethylthiazole- Z-mercaptothlazoiine. 0;. 2-mercaptoheuzoxazole- 2-methylbenzothiazole Benzoxazole 2-methylbenzoxazole Z-methylmercaptobonzothiazol 4,4-dimethyl'2 mercaptooxazoline illustration of the invention, but the invention is not to be limited thereby.

Example I I Gert nan silver utensilsimmersed in a solution of the detergentcompositionwithout tarnish" inhibitor turned bluerblack under the conditions ofYthe abovetest.

The importance of the mercapto group in the Z-position is demonstrated by the fact that-2-hydroxy-4-rnethylthiazo1e.;(SH.rep1aced' by, OH), 2-inethylmercaptobenzo thi'azoie (SH .replacedjby SCI-I benzothiazole (SHreplaced .by H), 'ben zoxazole. (SH replacedflb'y; H), 2- methylbenzothiazole (SI-I] replaced by CH5); and 2'- rnethylbenzoxazolefsH" replaced by CH showed no tarnishprotectibnat a concentration of'0.5%.

. x p e-1 L.

J Detergent: solutionsuwere; formulated by dissolving 1.7 g, of active". component; 2.4 g; offtetrasodiurnm pyi'o phosphate; and 12.5 mg. of Z-me'rcaptothiazolinerin one Note: (1) indicates barely noticeablotarnlsh; (2) indicates slight tarnish; (3)) indicates moderate tarnish; (4) indicatesheavy tarnish; (5) indicates very heavy tarnish.

Example II- Detergent compositions were. formulated by adding 0.015 to 0.50% by weightof the composition (0.03%

quartiofwater; (equivalent in amount. of active,. builder and inhibitor to 5 g. of the detergent composition of the preceding example plus 0.5% inhibitor by weight of the polyphosphate) and the same inhibition test was carried out as in the preceding example. Results are given below: 7

. Appearance of Active detergent: German silver Sodium salt of 1-dodecyloxy-2-propanol-3-sul-' .1 Yfonic acid a '(2) Sodium lauryl sulfate (2) Sodium salt of lauroyl methyl taurine (2) Sodium salt of the sulfoacetamide of aminoethyl laurate i Alkyl aryl polyethylene glycol ether (2) Polyethylene glycol oleater (1) As stated, the tarnish inhibitors of the invention are effective in amounts as low as 0.03% of the polyphosphate. The amount required for effective prevention of tarnishing depends in part, of course, upon the extent ;of protection afforded by the particular inhibitor used, and upon the particular phosphate and its concentration. An amount up to about 1% is satisfactory for tolylbiguanide and biphenylguanide.

aromatic sulfonic acids, such as thoseprepared by alkyla ting benzene or naphthalene with a kerosene fraction followed by sulfonation, aliphatic sulfonic acids, esters of sulfuric acid with aliphatic alcohols of 10 to 18 carbon atoms, particularly those derived bythe reduction of coconut oil, palm oil and like long-chain fatty acids; sulfonated castor oil, esters and ethers of isethionic acid,

the amides of'taurine and N-alkyl taurines, where the' fatty alcohols;

polyphosphate and pentapotassium tripolyphosphate, the

pyrophosphates A P O such as 'tetrasodinm pyrophosphate and tetrapotassium pyrophosphate, the hexameta- 'phosphates (APO -such as sodium hexametaphosphate and potassium hexameta'phosphate, and the tetrapolyphosphates A 1 0 such as hexasodium tetrapolyphosphate and hexapotassiumtetrapolyphosphate.

, Although the anti-tarnishing agents in accordance with the invention may beincorporated in any compositions containing polyphosphates', they are of particular application to' synthetic detergent compositions which contain such phosphatesas builders, and which are formulated with either anionic-or nonionic detergents. Such. detergent compositions should contain conventional propor tions of active detergent withinlthe range between 15 and 40%, polyphosphate in an amountbetween -5 and 50%, based on the total compositionand the residue builders and inert materials. v

The tarnish inhibitors in accordance with the invention are useful with a wide range of anionic andnonionic synthetic detergents. Of the anionic detergentsthe phenylpolypropylene sulfonates are particularly noteworthy. These sulfonates are characterized by th following structure;

insome respects, is generally considered to be a mem-' ber 'of the alkali metal family and acts'as though it were an alkali metal in these sulfonates. These are known compoundsfwhose' preparation and properties are 'set forth in U. S. 2,477,383 to Lewis,-issued July 26, 1949; they are available in commerce under the trade name Oronite.

' important "in tarnish" The invention is also applicable to water-soluble alkyl "1. to aqueous solutions containingpolyphosphates.

The detergent composition may contain other supplemental builders in addition to the polyphosphate, including alkali metal and alkaline earth metal sulfates, chlorides, silicates, borates, carbonates,- metaphosphates, and orthophosphates, such assodium silicate, magnesium sulfate, sodium carbonate, sodium sulfate, trisodium phosphate, potassium carbonate, sodium orthophosphate, sodiummetaphosphate, calcium sulfate, calcium chloride; sodium chloride, sodium borate, potassium metaphos phate and magnesium chloride. The builder should but need not be water-soluble) In addition to or-instead of the above-mentionedgsup-f plemental inorganic salts, organic materials such as starch, polyethylene glycols, polyvinyl alcohols and salts of car,- boxymethylcellulose may be used as builders. It has' been found that betweenabout 0.1 and 1% of an'alkali metal carboxymethylcellulose increasesdetergency and sudsing; i

Thefbuilder mixture is so chosen among alkaline,

neutral and acidic saltsffthat the composition ..obtained in preferred agents for bringing the pH' of the solutionl'to 1 a high alkaline value within the preferredrange'.

"The detergent composition is prepared by conventional mixturein a spray .or drum dryer at elevated tempera; tures- I pl" The tarnish inhibitorjmay be added to the detergent composition at any stage of its manufacture, to the finished detergent composition, or to the detergent solution.

Compositions containing tarnish inhibitors of the invention do not tarnish copper, or nickel copper alloys such as German silver alloy, Monel metal, coinage nickel, or brass, whichnormally tarnish when exposed It' is not possible at this time to explain why the compounds' of the invention are effective tarnish inhibitors. now ever, it has been observed "that'when a oerm n snver utensil is immersed for a'period in solution of the inhibitor and then immersed in a polyphosphate solu{ tion not containing inhibitor only slight tarnishing re-" sults. This is taken as an indication that inhibitor is preferentially adsorbed by the metal, and that this is prevention, but of'course, such evidence .is not conclusive. 1

Obviously, many modifications and variations may be made in the invention herein set forth Without departing from the spirit and scope thereof, and airy-suck limitations should be imposed as are indicated in the appended claims. i

The expression consisting essentially of as used arei essential to. the composition; namely, the tarnish inhibitor. and the alkali metal polyphosphate, and the expression does. not exclude other components from the composition whichdo not render it unsuitable for the desired purposes, such materials being, for instance, detergents, other builders, such as sodium silicate and sodium carbonate, carboxymethylcell'ulose, minor quantities of impurities, etc.

All parts and percentages in the specification and claims are by weight. Proportions of inhibitor are based on the weightof the polyphosphate unless otherwise indicated.

We claim:

1. A composition comprising a water-soluble polyphosphate which in aqueous solution tarnishes copper and copper and nickel alloys and a tarnish inhibitor in an amount to lessen the tarnishing action of the polyphosphate and having the general formula where Xis selected from the group consisting of oxygen and: sulfur and Z is a radicaltaken in sufiicient number to satisfy the free valences of the 4- and -ring carbon atoms and is selected from the group consisting of hydrogen, oxo oxygen, alkyl, arylzand saturated and unsaturated mono and polynuclear alicyclic and heterocyclic rings. condensed therewith. 1 i

2'. A composition in accordance with claim 1 in which the tarnish inhibitor is a thiazole.

3. A composition in accordance with claim 1 in which thetarnish inhibitor is a thiazoline.

4'. A composition in accordance with claim 1 in which the tarnish inhibitor is an oxazole.

5. A composition in accordance with'claim 1 in which the tarnish inhibitor is an oxazoline. i

6. A composition in accordance with claim 2 in which the tarnish inhibitor is 2-mercapto-4,5-dimethyl thiazole. 7'. A composition in accordance with claim 3 in which the tarnish inhibitor 1s Z-mercaptothiazoline.

8. A composition in accordance with claim 4 inwhich the tarnish inhibitor is 2-mercaptobenzoxazole.

9. A composition in accordance with claim 5 in which the tarnish inhibitor is Z-mercaptooxazoline.

10. A nonsoap detergent composition consisting essentially of an active organic detergent, a water-soluble polyphosphate which in aqueous solution tarnishes copper and copper and nickel alloys, and a tarnsh inhibitor in' an amount to lessen the tarnishing action of the polyphosphateand having the general formula where X is selectedfrom. the. group consisting of oxygen and sulfur and Z is a radical taken. in suflicient number to satisfy the free valences of the 4- and S-ring carbon atoms and; is selected from the group consisting, of-hy 13. A detergent composition in accordance with claim 10 in whic'liftlie' detergent is sodium phenyl polypropylene sulfonat'e'.

14. A nonsoap detergent composition consisting essentially of 'a'n alkali metal alkyl aryl sulfonate detergent, a water-soluble polyphosphate which in aqueous-solution tarnishescopper and-copper and nickelalloys and a tarnish-inhibitorin-a-n amount to lessen the" tarnishing action of the-polyphosphate and having the general formula- 1 where X is selected from the group consisting of oxygen and sulfur and Z is a radical taken in suflicient number to satisfy the free valences of the 4- and S-ring carbon atoms and is slected from the group consisting of hydrogen, oxo oxygen, alkyl, aryl and saturated and unsaturated mono and polynuclear'alicyclic and heterocyclic rings condensed therewith.

16. A detergent composition consisting essentially of an alkali metal phenyl polypropylene sulfonate detergent, pentasodium tripolyphosphate and a tarnish inhibitor in an amount to lessen the tarnishing action of the polyphosphate and having the general formula where X is selected from the group consisting of oxygen and sulfur and Z is a radical taken in sufficient number to satisfy the free valences of the 4- and S-ring carbon atoms and is selected from the group consisting of hydrogen, oxo oxygen, alkyl, aryl and saturated and unsaturated mono and polynuclear alicyclic and heterocyclic rings condensed therewith.

References Cited in the tile of this patent UNITED STATES PATENTS 1,773,024 Chapman Aug. 12, 1930 2,160,293 Shoemaker May 30, 1939' 2,238,651 Keenen Apr. 15, 1941 2,327,323 Teeters' Aug. 17, 1943 2,419,805 Wegst- Apr. 29, 1947 2,575,576 Bacon Nov. 20, 1951 2,618,603 Schaeffer. Nov. 18, 1952 2,618,605 Schaefier Nov. 18, 1952 

1. A COMPOSITION COMPRISING A WATER-SOLUBLE POLYPHOSPHATE WHICH IN AQUEOUS SOLUTION TARNISHES COPPER AND COPPER AND NICKEL ALLOYS AND A TARNISH INHIBITOR IN AN AMOUNT TO LESSEN THE TARNISHING ACTION OF THE POLYPHOSPHATE AND HAVING THE GENERAL FORMULA 